physics
posted by Stan on .
A woman is pushing a sofa at constant speed of 1.0 m/s on a horizontal surface. She exerts a horizontal force of 80 N in the direction of motion.
Approximately how hard would the woman have to push to keep the sofa moving at a constant speed of 2.0 m/s? explain
I am unsure how to calculate this

friction is the same, so the woman pushes with the force of friction to overcome it. She pushes again at 80N.
How hard would she push to keep it at any constant speed? 80N 
If she is pushing at constant speed, there is no net horizontal force.
Therefore the resisting force is 80 N at 1 m/s
I assume that the resisting force is mainly friction against the floor and will not change with speed.
Therefore once we accelerate the thing up to 2 m/s, it should proceed at that speed with the same old 80 N force.